Abstract: Method of laying pipelines on land, in which straight pipe pieces are aligned to each other above the trench route and are welded together, and the thus formed pipeline in welded condition is bent to an extent and in a direction defined by the trench route and subsequently is lowered down in a trench.

Abstract: A suction dredger installation provided with a vessel, at least one pump, at least one suction pipe hingedly connected to the vessel, said suction pipe comprising three pipe sections hingedly interconnected, the first of which is supported by a ladder, and together therewith being adapted for hinged movement relative to the vessel about a horizontal shaft extending thwartships and being connected to the second suction pipe section in lazy tong relationship, and means for controlling the position of the suction pipe, of which the control means for the position of the second suction pipe section are mounted on the ladder adjacent the pivot pin thereof with the vessel.

Abstract: A hopper barge having at least two longitudinal air chambers interconnected pivotally at deck level, which chambers in a loading position bound an upwardly open well and in an unloading position release a discharge opening at the bottom, and comprising at least one control unit for controlling the relative position of the air chambers, with per each control unit two synchronously controlled jack means, which are each pivotally connected with at least one of the air chambers by on the one end a lever arm, which two lever arms are arranged in substantially mirror-symmetrical relationship relative to the median longitudinal plane of the vessel and being interconnected pivotally, and on the other end a hinge fixedly secured to one of the air chambers.

Abstract: Method and apparatus for controlling the position of the last section of a suction pipe with a drag head, wherein the suction pipe comprises at least two pivotally connected sections and wherein there are provided at least two independently operable hoisting winches for the suction pipe and wherein the hoisting installations are operated so that the last section of the suction pipe with drag head is kept at a specific, pre-determined angle of inclination.

Abstract: A hydraulic synchronous driving mechanism provided with at least two piston-cylinder assemblies, each having a bottom chamber and a ring chamber and the piston rods of which engage a counterdevice adapted to synchronously load piston rods mutually in opposite directions, a hydraulic fluid circuit provided with at least a pump and a reservoir, whereby there are pair-wise arranged volumetric pump-motors in fluid lines throughconnected to the bottom chamber of the one cylinder and the ring chamber of the other cylinder, which pump-motors are mutually coupled for a constant supply ratio, while the fluid line sections extending from the pump-motors to the cylinders are throughconnected to only one cylinder chamber.